Asteroids are commonly classified into groups based on the characteristics of their orbits and on the details of the spectrum of sunlight they reflect.

Stories of asteroid mining became more and more numerous since the late 1940s, with the next logical step being depictions of a society on terraformed asteroids —in some cases dug under the surface, in others having dome colonies and in still others provided with an atmosphere which is kept in place by an artificial gravity.

Moreover, depictions of the AsteroidBelt as The New Frontier clearly draw (sometimes explicitly) on the considerable literature of the Nineteenth-Century Frontier and the Wild West.

Trojanasteroids are asteroids that orbit in gravitationally stable Lagrange points in a planet'sorbit, either trailing it or preceding it (these places are where the gravitational attraction of the Sun and of the planet balance each other).

Asteroid 4179 Toutatis (formerly 1989 AC) was discovered by C. Pollas on January 4, 1989, at Caussols, France, on photographic plates taken on the 0.9-m Schmidt telescope by Alain Maury and Derral Mulholland during astrometric observations of Jupiter's faint satellites.

The inversion solved for the asteroid's shape and inertia tensor, their orientation with respect to each other, initial conditions for the asteroid's spin and orientation, the radar scattering properties of the surface, and the projected location of the asteroid's center of mass in each frame.

The asteroid's1996 approach was not as close as in 1992, and Arecibo was unavailable (that telescope was being upgraded), but Goldstone was used for high-resolution imaging on nine straight dates.

The asteroid, dubbed 2002 NT7, is travelling at 28 kilometres per second and there is a chance, initial calculations indicate, that it could hit our planet on February 1, 2019.

Astronomers believe the asteroid, discovered through the Linear Observatory's automated sky survey programme in New Mexico in the U.S. on July 5, could be the most threatening object yet detected in space.

It is the first object to be given a positive value, of 0.06, on the Palermoscale of potential threat posed by asteroids, although scientists said further calculations were needed to pin the precise path of 2002 NT7.

Japan's Hayabusa spacecraft is set to perform the first of three daring rendezvous with a small asteroid on Friday, as planetary scientists puzzle over close-up images of the space rock.

While most asteroids appear to be covered largely by regolith — powdery material created when small meteorites crash into a rocky body — Itokawa's surface shows only small amounts of the pulverised stuff.

This, along with Hayabusa's discovery that the asteroid's density is less than expected, leads Bottke to believe it may be composed of smaller rocks that are held together by gravity.

The scientific answer is that it is possible that an asteroid or comet could beltearth, this explosive impact with our world causing global destruction, a nuclear worldwide firestorm, and later cutting off the sunlight similar to a nuclear winter, but the odds are so small that it is not worth worrying about.

This asteroid has an orbital period around the sun of 837 days and 1.2 miles wide, giving it enough kinetic energy to be a doomsday asteroid.

For example, the asteroid that destroyed the dinosaurs millions of years ago is believed to have hit in the Yucatan of Mexico.

A pair of 35-million-year-old craters on Earth thought to have been carved by comets now appears to be the result of a broken asteroid that generated a slowly delivered shower of debris over millions of years.

Other studies have found that when asteroids collide and break apart, their fragments can move from the asteroidbelt between Mars and Jupiter to reach Earth's vicinity over long time periods.

The asteroid that broke up to produce the asteroid shower "was much bigger" and "should have produced many more fragments than the two that came on an Earth collision course," Claeys said.

Asteroid Douglasadams was among the 71 newly named celestial objects announced Tuesday by the International Astronomical Union's Minor Planet Center in Cambridge, Mass.

But Adams' asteroid should hold special appeal for fans of science fiction and pop culture: His "Hitchhiker" saga, which traces the adventures of a motley interplanetary crew after Earth is destroyed to make way for a hyperspace bypass, started out as a BBC radio comedy.

For example, the "Arthurdent" asteroid was so named at the suggestion of the man who actually found it, German astronomer Felix Hormuth.

www.msnbc.msn.com /id/6867061 (964 words)

USATODAY.com - Asteroid-eating robots considered for Earth's protection(Site not responding. Last check: )

Their weapon: a swarm of nuclear-powered robots that could drill into an asteroid and hurl chunks of it into space with enough force to gradually push it into a non-Earth impacting course.

At the heart of the MADMEN concept is a mass driver, which would eject asteroid material as it is drilled out of the rock and sling it out into space using electromagnetic acceleration.

The key, they said, is to have a lander on each face of an asteroid working together autonomously to push the space rock in one direction as it tumbles through space.

I've ceased posting asteroid occultation predictions of my own; it's a tough thing to keep up with, and several people are doing a better job of it than I probably would anyway.

The asteroid is usually a small fraction of an arcsecond in diameter, which means that if your position for the star or the asteroid is off by that amount, your prediction will be off by an entire path width.

Unless clicking on an entry in the "asteroid occultation table" has already done it for you, you should set up Guide for the approximate date/time of the event, and "go to" either the asteroid or the star that is going to be occulted.